Feeding device for rock drills



Q l M M & s

INVENTOR BY gv K JOHN c. cu/er/ ATTORNEY Nov. 13, 1934. J. c. CURTIS FEEDING DEVICE FOR ROCK DRILLS Filed May 2, 1952 Patented Nov. 13, 1934 UNITED STA res PATENT OFFICE Cleveland Rock Drill Company,

Ohio, a. corporation of Ohio Cleveland,

Application May 2, 1932-, Serial No. 608,638

8 Claims.

This invention relates broadly to rock drills, but is more particularly concerned with feeding mechanism for rock drills of the drifter type.

One object of this invention is to provide improved and compact feeding mechanism for rock drills.

Another object of this invention is to provide a rock drill of the drifter type with a feeding mechanism wherein the distance from the supporting or attaching cone to the center axis of the machine is reduced to a minimum, diminishing thereby the deleterious efiect of vibrations.

Other objects and advantages reside in the specific construction and aggroupment of elements peculiar to this structure as will become apparent from a more complete examination of this specification, where there are assembled and pointed out certain combinations of parts and specific constructionindicative of the scope and spirit of the invention.

Fig. 1 is a longitudinal view-partly in section illustrating a rock drill embodying the invention.

Fig. 2 is a cross sectional view taken in a plane indicated by line 2-2 in Fig. 1.

Fig. 3 is a view similar to 2 taken in a plane indicated by line 3--3 in Fig. 1.

Fig. 4 is a rear end view of a portion of the feeding mechanism.

Fig. 5 is a longitudinal elevational view illustrating the portion of the feeding mechanis shown in Fig. 4.

Fig. 6 is a cross sectional view taken in a plane indicated by line 6-6 in Fig. 5.

Fig. '7 and 8 are views similar to Fig. 6 illustrating the throttle valve in different positions.

Fig. 9 is a top plan view of the feed tube constructed in accordance with the invention.

Referring now to the drawing, the rock drill shown for the purpose of illustration comprises a cylinder 10 within which there is reciproc'ably mounted a piston capable of delivering its blows to a drill steel 11. The drill steel is conveniently mounted within a chuck 12 which is journaled within a front housing 13, secured to the cylinder 10 by a pair of side bolts 14. Longitudinally disposed on each side of the cylinder 10, there is provided a slot 15 defining, with the lower face of the cylinder, a gib l6.

The feeding mechanism comprises a tubular member 17 made of rectangular cross section. At a convenient distance from the ends thereof, there is attached thereto a cone 18 which may be affixed in any suitable manner. The cone 18 may for instance be provided with two-parallel walls 19, which may be spot welded to the tube 1'7, and to assure a better integral attachment the edge of the wall may also be welded to the tube. The bottom wall of the tube may also be cut away and the cone manufactured to fit within this cut-away portion as illustrated at. 20. For a portion of its length, the tube 17 is provided with two longitudinally disposed guide members 21, which are secured upon the upper face of the tube by a weld 22 extending the full length of the guides. These guides are bent at right angle for engagement within the cylinder slots 15 and define, with the upper external wall of the tubular member 17, a pair of ways 23 within which the cylinder gibs 16 are slidably mounted, the lowerportion of the cylinder being slidably supported by the upper wallof the tubular member 1'7. Toward the right, the tubular member 1-7 has its upper wall manufactured with a cut-away portion or slot 24, the'purpose of which will be explained later.

Reciprocably mounted within the tubular member 17, there is a rectangular piston 25 provided with a plurality of packing members 25' to assure, the fluid-tight engagement of the piston within the feed'tube l7. The rightward travel of the piston 25 is limited by a stationary bushing 26, which is secured within the feed tube by a plurality of bolts 27. SlidabIy mounted through the bushing 26 in fluid tight engagement therewith, there is a piston rod 28 having one of its ends affixed to the piston 25 by a bolt 2 9.' The other end of the piston rod 28 is bent at'fright angle for engagement within a bore 30, transversally disposed within the front housing 131 The leftward movement of the piston 25 is limited by a backhead 31'secured to the outer end of the tubular member 17 by a plurality of bolts 32. Rotatably mounted within the backhead 31-, there is a throttle valve 33 formed with a central bore 34. Adjacent the end of .the throttle valve, the backhead is. provided with a screw threaded bore 35 within which may be aflixed the end of a fluid conduit thrugh which motive fluid may be admitted in the throttle valve bore 34. Provided within the throttle valve 33, there is disposed, in the same vertical plane, a passage 36 and groove 3'7. In another vertical plane, there is also disposed a passage 38 and groove 39. Motive fluid may be admitted into the left end of the feed tube 17 by a passage or port 40, and into the front or right end of the feed tube 17, through a passageway 41, formed withina restriated tube 42 mounted under the feed tube 17.

When it is desired to feed the rock drill forwardly or toward the right, the throttle valve, by

28, thus imparting a longitudinal displacement of the drill upon the feed tube 17 and within the guideways 23. If it is desired to maintain the drill in a stationary position, the throttle valve 33 may be positioned as illustrated in Fig. '7. In this posi tion, motivefluid is restrictively admitted into the rear end of the feed tube 17 through the passage 36 partly registering with theport 40, thus ad-' mitting a small amount of motive fluid within the rear end of the feed tube 1'7. Simultaneously the passageway 41 leading-into the front portion of the feed tube 17, is closed by the throttle valve 33, thus, preventing the motive fluid previously admitted into that portion of the cylinder to escape therefrom. The pressure fluid restri'ctively ad mitted into the rear end of the feed tube 1'7, will move the piston 25 forwardly until the, pressure fluid into the front end of the feed tube is compressed sufficiently by the piston 25 to overcome the action of the pressure fluid on the enlarged area of the piston, preventing thereby a further displacement of the piston within the feed tube 25.

When it is desired to feed the rock drill rear- Wardly or toward the left, the throttle valve-may be positioned as illustrated in Fig. 6. I In this position of the throttle valve, motive fluid will be ad mitted into the forward end of the feed .tube 17 through the valve passage '38, and passageway .41. The rearward end of the feed tube being simul. taneously exhausted to atmosphere through the port 40, valve groove 37, and'orifice 45, the piston 25, by theaction of motive fluid thereon, will move rearwardly or toward the left. Thisfmoveme nt will-be transmitted tothe rock drill by thepiston rod 28, Jthus imparting a longitudinal rearward displacement of the machines within the ways 23. During the longitudinal displacement of the rock drill, the end of the piston rod28 'in engagement within the front housing 13, is free to travel within thev slot 24 provided in the upper wall "of the lustrated in Fig. 2, with the lower and'upper' walls thereof being longer than "the, side walls, 'f the distance from thesupportin'g cone 18 to the'cen ter axis of the rock drill is reduced to a'minimum. With a cylindrical feed tube of a cross sectional area equal to the crossjjsectional areaofarectangular feed tube, the distance between the center axis of the rock drill to'the supporting cone would have to be considerably greater, increasing'thereby the vibratory impulse transmitted from the machine to the feeding mechanism. V i 1 Although the foregoing description is'necessa+ rily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive orconfining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from'the scope or spirit of the invention as herein claimed.

I claim:

1. In combination with a drilling motor, of

tor, reducing thereby the distance between the center axis of the motor and the feed tube.

2. In combination with a drilling motor, of feeding means therefor comprising a feed tube of non-circular cross sectional area, a fluid actuated pistonlongitudinally movable within said feed tube, guideway within which said drilling motor is slidably mounted, means for transmittingthelongitudinal movement of said piston to said drilling motor, the distance between said drillingmotor and. the longitudinal center axis of said feed tube being-less than the radius of a cylindrical feed tube of equal or greater cross sectional area. I I

3. In combination with ing means therefor comprising a feed tube. of non-circular cross sectional area, a supporting cone secured to said feed tube, a fluid actuated piston longitudinallymovable .within said feed tube, guideway within which said drilling motor is slidablymounted, means fortransmitting the longitudinal movement of said piston .to said drilling motor, the distance between said cone and said drilling motor being less than the diameter of a cylindrical feed tube of equal or greater cross sectional area. i i, 4'. In combination with a drilling motor, of feeding means thereforeomprising a feed'tube of non-circular cross section, a fluid actuated member longitudinally movable withinsaid tube, guideways within which "said drilling motor is slidably mounted, means for transmitting the longitudinal movement of "'said'member to said drilling motor, the distance between the center axis of said drilling motor. andthe center of said feed tube being less than the corresponding distance of a drillingmotonequipped with a' feed cylinder of circular cross sectional area equal to or greater than the area of thenon-circular section of said feed tubeJE 1 5. In combination with a drilling. motor, of feeding means therefor comprising a feed tube of noncircular cross section disposed invertical alignment with respect to said drilling motor,v a fluid actuated member longitudinally movable within said tube, guideways within which said drillingmotor is slidably. mounted, means for transmitting the longitudinal movement. of said member to said drilling-motor, the vertical extent of the cross section of said tube'being lessthan its horizontal extent, reducing thereby the dis-. tance between the center axis of saiddrilling mos torand of said feed tube.

6'. In combination with a drilling motor, of feeding means therefor comprising a feed tube of non-circular cross section located in vertical alignment with said drilling 'motor, a feeding member for saiddrilling motor movable within said feed tu'be, a supportupon which said drilling motoris'free to slide,-the vertical extent of the cross section'of said'feed tube being less than the diaineteriof afeed cylinderhaving-a cross sectionalrarea equal to or greater than that of said feed tube. .7. In combinationwitha drilling motor, or

a drilling motor, a feedfeeding means therefor comprising a feed tube of non-circular inner cross section, a feeding member for said drilling motor movable within said feed tube, a support upon which said drilling motor is free to slide, the extent of the inner cross section of said feed tube taken in a plane passing through the center axis of said drillin motor and of said feed tube being less than the diameter of a feed cylinder having an internal cross sectional area equal to or greater than that of said feed tube.

8. In combination with a drilling motor, of a support therefor, comprising a housing having guideways within which said motor is slidably mounted, said housing being formed of a noncircular internal cross section, a feeding mechanism within said housing associated with said drilling motor, the extent ofthe internal cross section of said housing taken in a plane passing through the center axis of said drilling motor and of said housing being less than the inner diameter of a substantially cylindrical housing having an internal cross'sectiona-l area equal to or greater than that of said housing.

JOHN C. CURTIS. 

